In fact, the “traditional” way of playing closed guard is one of the most effective and safest ways of approaching guards that Jiu Jitsu has to offer...
A very cool entry is through a failed Kimura. Sometimes, people are simply too strong, or you mistimed your Kimura and they extend their arm, preventing you from attacking the shoulder...
For the octopus half guard, you need to go under the far side arm when looking to get to the octopus position...
Getting to either the full or half octopus guard is going to put you in a position to reverse the tables immediately...